1. Technical Field
The present disclosure relates to relays.
2. Description of Related Art
Generally, a relay may include a movable contact, a stationary contact, a coil, an iron core inside the coil, a transistor, and a power source. Usually, the movable contact is electrically connected to the power source, and the stationary contact is connected to an output terminal of the relay. One end of the coil is connected to the power source, and the other end of the coil is connected to a collector of the transistor, an emitter of the transistor is grounded. The transistor is turned on when a control voltage is applied to a base of the transistor, to cause a current through the coil, and the coil produces an electromagnetic field accordingly. The iron core thus attracts the movable contact and causes the movable contact to make contact with the stationary contact, and then the relay can output a voltage. However, in such a relay, if the relay needs to output voltage for a long time, the control voltage must constantly be applied to the base of the transistor, thus resulting an excess of power consumption.
Therefore, it is desirable to provide a relay to overcome the described limitations.